Timed instrumental activities of daily living tasks: Relationship to visual function in older adults

Purpose. To identify instrumental activities of daily living (IADL) tasks w hose completion time is related to visual function in older adults. Methods . Visual function (acuity, contrast sensitivity, and useful field of view) and the time to complete 17 visual tasks of everyday life were measured in a sample of 342 older adults (mean age 71 years, range 56 to 86) recruited from eye clinics. The timed IADL (TIADL) tasks included a variety of visual activities such as reading ingredients on cans of food and instructions on medicine bottles, finding a phone number in a directory, locating items on a crowded shelf and in a drawer, and using a screwdriver. Results. Multipl e regression analysis indicated that poorer scores for acuity, contrast sen sitivity, and useful field of view were independently associated with longe r times to complete visual TIADL tasks, even after adjusting for age, educa tional level, depression, and general health. Cognitive status also had a s ignificant, independent association with timed task performance. Conclusion s. Older adults' timed performance in everyday tasks is related to various aspects of visual function independent of the influences of other functiona l and health problems and advanced age. This suggests that TIADL tasks may eventually be useful as performance outcomes in intervention evaluations ta rgeted at reversing vision impairment or minimizing its impact. To understa nd the relationship between vision impairment and TIADL task performance in older adults, cognitive impairment needs to be taken into account because it has a relatively strong and independent relationship with visual TIADL t ask performance.